In recent years, with an increase in the size of semiconductor substrates and image display devices, optical components such as large lenses and mirrors are often employed in lithographic techniques for forming patterns on them. These optical components normally have surfaces which are processed or on which a variety of thin films such as coating films are formed.
A sputtering method is employed to uniformly deposit a multilayer film on a substrate for a concave/convex optical system used in, for example, an exposure machine. Setting the target area of a cathode for use in sputtering smaller than the substrate allows an improvement in use efficiency of the target and deposition which is suitable for the three-dimensional patterns of various types of substrates and is impossible when a large target is used.
To uniformly deposit a multilayer film on a substrate for a concave/convex optical system, the distance (TS distance) between the target and the substrate for optics must be kept constant. To achieve this, PTL1 discloses a technique of controlling three or more axes such as the rotation axis of the cathode and the spin axis and scan axis of the substrate.
Also, PTL2 discloses a technique of adjusting the pressure in accordance with the distance between a target and a substrate for an optical system.